H Pylori
Copyright ©The Author(s) 2004. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 1, 2004; 10(17): 2498-2502
Published online Sep 1, 2004. doi: 10.3748/wjg.v10.i17.2498
Construction of attenuated Salmonella typhimurium Strain expressing Helicobacter pylori conservative region of adhesin antigen and its immunogenicity
Yang Bai, Ya-Li Zhang, Ji-De Wang, Zhao-Shan Zhang, Dian-Yuan Zhou
Yang Bai, Ya-Li Zhang, Ji-De Wang, Dian-Yuan Zhou, PLA Institute for Digestive Medicine, Nanfang Hospital, the First Military Medical University, Guangzhou 510515, Guangdong Province, China
Zhao-Shan Zhang, Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China
Author contributions: All authors contributed equally to the work.
Supported by the National Natural Science Foundation of China, No. 30270078
Correspondence to: Dr. Yang Bai , PLA Institute for Digestive Medicine, Nanfang Hospital, the First Military Medical University, Guangzhou 510515, Guangdong Province, China. baiyang1030@hotmail.com
Telephone: +86-20-61641532
Received: November 4, 2003
Revised: January 4, 2004
Accepted: January 12, 2004
Published online: September 1, 2004

AIM: To construct a non-resistant and attenuated Salmonella typhimurium (S. typhimurium) strain which expresses conservative region of adhesion AB of Helicobacter pylori (H pylori) and evaluate its immunogenicity.

METHODS: The AB gene amplified by PCR was inserted into the expression vector pYA248 containing asd gene and through two transformations introduced into the delta Cya, delta Crp, delta Asd attenuated Salmonella typhimurium strain, constructing balanced lethal attenuated Salmonella typhimurium strains X4072 (pYA248-AB). Bridged ELISA method was used to measure the expression of AB antigen in sonicate and culture supernatant. According to the method described by Meacock, stability of the recombinant was evaluated. Semi-lethal capacity test was used to evaluate the safety of recombinant. The immunogenicity of recombinant was evaluated with animal experiments.

RESULTS: The attenuated S. typhimurium X4072 (pYA248-AB) which expresses AB was successfully constructed. Furthermore, bridged ELISA assay showed that the content of AB in recombinant X4072 (pYA248- AB) culture supernatant was higher than that was in thallus lytic liquor. And after recombinant X4072 (pYA248- AB) was cultured for 100 generations without selection pressure, the entire recombinant bacteria selected randomly could grow, and the AB antigen was defected positive by ELISA. The growth curve of the recombinant bacteria showed that the growth states of X4072 (pYA248) and X4072 (pYA248-AB) were basically consistent. The survival rate of C57BL/6 was still 100%, at 30 d after mice taking X4072 (pYA248-AB) 1.0 × 1010 cfu orally. Oral immunization of mice with X4072 (pYA248-AB) induced a specific immune response.

CONCLUSION: In vitro recombinant plasmid appears to be stable and experiments on animals showed that the recombinant strains were safe and immunogenic in vitro, which providing a new live oral vaccine candidate for protection and care of H pylori infection.

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